Am J Physiol Cell Physiol AJP: Gastrointestinal and Liver Physiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Cell Physiol 273: C1889-C1899, 1997;
0363-6143/97 $5.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Awayda, M. S.
Right arrow Articles by Benos, D. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Awayda, M. S.
Right arrow Articles by Benos, D. J.
Vol. 273, Issue 6, C1889-C1899, December 1997

Regulation of a cloned epithelial Na+ channel by its beta - and gamma -subunits

Mouhamed S. Awayda1, Albert Tousson2, and Dale J. Benos3

1 Department of Medicine and Department of Physiology, Tulane University School of Medicine, New Orleans, Louisiana 70112; and 2 Department of Cell Biology and 3 Department of Physiology and Biophysics, University of Alabama at Birmingham, Birmingham, Alabama 35223

Using the Xenopus oocyte expression system, we examined the mechanisms by which the beta - and gamma -subunits of an epithelial Na+ channel (ENaC) regulate alpha -subunit channel activity and the mechanisms by which beta -subunit truncations cause ENaC activation. Expression of alpha -ENaC alone produced small amiloride-sensitive currents (-43 ± 10 nA, n = 7). These currents increased >30-fold with the coexpression of beta - and gamma -ENaC to -1,476 ± 254 nA (n = 20). This increase was accompanied by a 3.1- and 2.7-fold increase of membrane fluorescence intensity in the animal and vegetal poles of the oocyte, respectively, with use of an antibody directed against the alpha -subunit of ENaC. Truncation of the last 75 amino acids of the beta -subunit COOH terminus, as found in the original pedigree of individuals with Liddle's syndrome, caused a 4.4-fold (n = 17) increase of the amiloride-sensitive currents compared with wild-type alpha beta gamma -ENaC. This was accompanied by a 35% increase of animal pole membrane fluorescence intensity. Injection of a 30-amino acid peptide with sequence identity to the COOH terminus of the human beta -ENaC significantly reduced the amiloride-sensitive currents by 40-50%. These observations suggest a tonic inhibitory role on the channel's open probability (Po) by the COOH terminus of beta -ENaC. We conclude that the changes of current observed with coexpression of the beta - and gamma -subunits or those observed with beta -subunit truncation are likely the result of changes of channel density in combination with large changes of Po.

oocyte expression; immunofluorescence; Liddle's syndrome; channel activation


This article has been cited by other articles:


Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
K. Sobczak, A. Willing, K. Kusche, N. Bangel, and W.-M. Weber
Amiloride-sensitive sodium absorption is different in vertebrates and invertebrates
Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2007; 292(6): R2318 - R2327.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Renal Physiol.Home page
G. Capasso, M. Rizzo, C. Evangelista, P. Ferrari, G. Geelen, F. Lang, and G. Bianchi
Altered expression of renal apical plasma membrane Na+ transporters in the early phase of genetic hypertension
Am J Physiol Renal Physiol, June 1, 2005; 288(6): F1173 - F1182.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Renal Physiol.Home page
S. W. Kim, W. Wang, J. Nielsen, J. Praetorius, T.-H. Kwon, M. A. Knepper, J. Frokiaer, and S. Nielsen
Increased expression and apical targeting of renal ENaC subunits in puromycin aminonucleoside-induced nephrotic syndrome in rats
Am J Physiol Renal Physiol, May 1, 2004; 286(5): F922 - F935.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Renal Physiol.Home page
J. Nielsen, T.-H. Kwon, J. Praetorius, Y.-H. Kim, J. Frokiaer, M. A. Knepper, and S. Nielsen
Segment-specific ENaC downregulation in kidney of rats with lithium-induced NDI
Am J Physiol Renal Physiol, December 1, 2003; 285(6): F1198 - F1209.
[Abstract] [Full Text]

Home page
 HypertensionHome page
C. Nicco, M. Wittner, A. DiStefano, S. Jounier, L. Bankir, and N. Bouby
Chronic Exposure to Vasopressin Upregulates ENaC and Sodium Transport in the Rat Renal Collecting Duct and Lung
Hypertension, November 1, 2001; 38(5): 1143 - 1149.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Cell Physiol.Home page
S. J. Copeland, B. K. Berdiev, H.-L. Ji, J. Lockhart, S. Parker, C. M. Fuller, and D. J. Benos
Regions in the carboxy terminus of {alpha}-bENaC involved in gating and functional effects of actin
Am J Physiol Cell Physiol, July 1, 2001; 281(1): C231 - C240.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
H.-L. Ji, C. M. Fuller, and D. J. Benos
Peptide Inhibition of Constitutively Activated Epithelial Na+ Channels Expressed in Xenopus Oocytes
J. Biol. Chem., December 31, 1999; 274(53): 37693 - 37704.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
B. Jovov, A. Tousson, H.-L. Ji, D. Keeton, V. Shlyonsky, P.-J. Ripoll, C. M. Fuller, and D. J. Benos
Regulation of Epithelial Na+ Channels by Actin in Planar Lipid Bilayers and in the Xenopus Oocyte Expression System
J. Biol. Chem., December 31, 1999; 274(53): 37845 - 37854.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
M. L. Chalfant, J. S. Denton, A. L. Langloh, K. H. Karlson, J. Loffing, D. J. Benos, and B. A. Stanton
The NH2 Terminus of the Epithelial Sodium Channel Contains an Endocytic Motif
J. Biol. Chem., November 12, 1999; 274(46): 32889 - 32896.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
A. Naray-Fejes-Toth, C. Canessa, E. S. Cleaveland, G. Aldrich, and G. Fejes-Toth
sgk Is an Aldosterone-induced Kinase in the Renal Collecting Duct. EFFECTS ON EPITHELIAL Na+ CHANNELS
J. Biol. Chem., June 11, 1999; 274(24): 16973 - 16978.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
K. F. Harvey, A. Dinudom, P. Komwatana, C. N. Jolliffe, M. L. Day, G. Parasivam, D. I. Cook, and S. Kumar
All Three WW Domains of Murine Nedd4 Are Involved in the Regulation of Epithelial Sodium Channels by Intracellular Na+
J. Biol. Chem., April 30, 1999; 274(18): 12525 - 12530.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Renal Physiol.Home page
D. B. Mount, A. Baekgaard, A. E. Hall, C. Plata, J. Xu, D. R. Beier, G. Gamba, and S. C. Hebert
Isoforms of the Na-K-2Cl cotransporter in murine TAL I. Molecular characterization and intrarenal localization
Am J Physiol Renal Physiol, March 1, 1999; 276(3): F347 - F358.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
K. F. Harvey, A. Dinudom, D. I. Cook, and S. Kumar
The Nedd4-like Protein KIAA0439 Is a Potential Regulator of the Epithelial Sodium Channel
J. Biol. Chem., March 9, 2001; 276(11): 8597 - 8601.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
A. Dinudom, K. F. Harvey, P. Komwatana, C. N. Jolliffe, J. A. Young, S. Kumar, and D. I. Cook
Roles of the C Termini of alpha -, beta -, and gamma -Subunits of Epithelial Na+ Channels (ENaC) in Regulating ENaC and Mediating Its Inhibition by Cytosolic Na+
J. Biol. Chem., April 20, 2001; 276(17): 13744 - 13749.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online